The bq24133 device is a highly integrated stand-alone Li-Ion and Li-Polymer switched-mode
battery charger with two integrated N-channel power MOSFETs. The device offers a constant-frequency
synchronous PWM controller with high accuracy regulation of input current, charge current, and
voltage. The bq24133 closely monitors the battery pack temperature to allow charge only in a preset
temperature window. The bq24133 charges one, two, or three cells (selected by CELL pin) at a fixed
The bq24133 charges the battery in three phases: preconditioning, constant current, and
The bq24133 provides power path selector gate driver ACDRV/CMSRC on input NMOS pair ACFET
(Q1) and RBFET (Q2), and BATDRV on a battery PMOS device (Q3). When the qualified adapter is
present, the system is directly connected to the adapter. Otherwise, the system is connected to the
battery. In addition, the power path prevents battery from boosting back to the input.
The bq24133 charges the battery from a DC source as high as 17 V, including a car
battery. The input overvoltage limit is adjustable through the OVPSET pin. The AVCC, ACP, and ACN
pins have a 30-V rating. When a high-voltage DC source is inserted, Q1 and Q2 remain off to avoid
high-voltage damage to the system.
For 1-cell applications where the battery is not removable, the system can be directly
connected to the battery to simplify the power path design and reduce the cost. With this
configuration, the battery can automatically supplement the system load if the adapter is
The bq24133 is available in a 24-pin, 5.5-mm × 3.5-mm thin VQFN package.